<?php
class Dvd {
    public function open() {
        echo "打开dvd<br>";
    }
    public function run() {
        echo "dvd播放<br>";
    }
    public function unRun() {
        echo "dvd停止播放<br>";
    }
    public function close() {
        echo "关闭dvd<br>";
    }
}